PORTABLE TRAFFIC
MONITORING SITE
INSTALLATION AND
INSPECTION TRAINING
PRESENTED BY:
FLORIDA DEPARTMENT OF
TRANSPORTATION AND SOUTHERN TRAFFIC
SERVICES
RUBIE FRASE & TERRY ROBINSON
THE IMPORTANCE OF
DATA COLLECTING
•
The State Road Department started
collecting traffic data at ten locations
back in 1936. As the state grew both
in population and number of lane
miles, the need to expand traffic data
collection was obvious.
THE IMPORTANCE OF
DATA COLLECTING
•
The value of good traffic data
became apparent early on in the
evolution of the national
Department of Transportation
(DOT) and eventually the Federal
Highway Administration (FHWA).
THE IMPORTANCE OF
DATA COLLECTING
•
This data is translated into
revenue allocations for the
state and federal highway
programs.
THE IMPORTANCE OF
DATA COLLECTING
Good data is a result of good site installations. Good
count/speed/vehicle classification and weight data
is essential to the following customers:
Some Internal Uses:
• Roadway Design uses our data to determine if
facility enhancements/lane additions are needed;
• Pavement Design uses our data to determine
pavement type & thickness requirements;
• Traffic Operations/Maint. Use it to determine lane
closure restrictions. And there are many others.
THE IMPORTANCE OF
DATA COLLECTING
Data uses (cont.)
Some External Uses:
• The FHWA compiles data for use in national
trend reports, national Truck Weight Study and
other studies and for apportioning funds back
to us;
• Advertisers and developers that need to know
how many motorists are passing a given
location in order to set sign and rates or
determine potential demand for retail outlets,
etc. (among many others).
THE IMPORTANCE OF
DATA COLLECTING
•
Two categories of traffic
monitoring sites have permanent
equipment physically located in
the roadway. These are TTMS and
PTMS. They are the backbone of
the traffic count program
administered by the FDOT Central
and District Offices.
THE IMPORTANCE OF
DATA COLLECTING
•
The data collected at these sites
may include: volume, speed,
vehicle class and weight. The
type of equipment installed and
the programs set-up in the
equipment determine how the site
functions.
TTMS
TTMS
TELEMETERED TRAFFIC MONITORING SITE
•
•
•
TTMS sites are the locations that are polled via
modem daily by the TRANSTAT Central Office
computers. They record and transmit every day
of the year and provide the data used for
adjusting short-term traffic counts to Annual
Average Daily Traffic (AADT).
TTMS sites are installed and maintained out of
Central Office in Tallahassee.
Many have solar panels
PTMS
TYPE II BASE
MOUNTED
TYPE III PEDESTAL
MOUNTED
PTMS
PORTABLE TRAFFIC
MONITORING SITE
•
PTMS locations are usually installed on
high volume urban arterials where
rubber hose counts or other
equipment is difficult to install and
maintain.
PTMS
•
Loop
Piezo
The permanent part of the installation
is the cabinet and loop/piezo wires
installed in the pavement. Greater
reliability, personnel safety, and
accuracy are the reason loops and
piezos are preferred to hose counts.
PTMS
LOOP
•
PIEZO
Loops provide a volume count of
vehicles crossing the loop sensors.
The piezos provide classification count
which measures the axles as the
vehicle crosses the piezo.
PTMS
•
To gather data, a traffic counter is
normally placed in the cabinet and
attached to the wire harness for a
short period (2 – 7 days) either
annually or quarterly, then moved
from one site to another, hence the
term portable traffic monitoring site.
PTMS
ADR-1000 COUNTER IN CABINET
HISTORY OF
ISSUES
Issue – PTMS Inspections Not Passing
• Resolution – Train DOT, Construction,
Contract and Sub-contract employees on
how to install a PTMS site.
OBJECTIVE FOR
THIS CLASS
•
•
Above all, the need to follow Design
Standards and Plan Specifications.
Design standards are reviewed every
year and changes made as needed.
You need to keep a copy of the latest
standards with you at all times.
The following slide reflects a major
change to loops.
OBJECTIVE FOR
THIS CLASS
Square
Corners
OBJECTIVE FOR
THIS CLASS
•
Above all, the need to follow Design
Standards and Plan Specifications.
Review the plans and follow the
placement, materials to be used and
location precisely.
• For Example: Loops are no longer to be
cut at a 45° angle. Since the year 2001
the standard is to drill corners with a 1.5”
bit by 2” minimum depth.
OBJECTIVE FOR
THIS CLASS
•
Above all, the need to follow Design
Standards and Plan Specifications.
Loops SHOULD NOT be cut across
the concrete joint in the roadway. As
the vehicles travel across the
pavement, the pavement jars and
could loosen the loop wires and render
them useless.
OBJECTIVE FOR
THIS CLASS
OBJECTIVE FOR
THIS CLASS
•
Above all, the need to follow Design
Standards and Plan Specifications.
Piezos come with a warranty card.
The warranty card must be filled out
and a copy of it placed in the cabinet
along with a copy of the cabinet
schematics.
OBJECTIVE FOR
THIS CLASS
OBJECTIVE FOR
THIS CLASS
Above all, the need to follow Design
Standards and Plan Specifications.
The difference between a good and
bad site!
Good
Bad
OBJECTIVE FOR
THIS CLASS
Above all, the need to follow Design
Standards and Plan Specifications.
•
Every time a site does not
pass on the first inspection is
wasted tax payer’s money.
This affects all of us including
you.
GOING
FORWARD
•
The plans are delivered to the Data
Collection Manager, and they review
them for proper location, design and
placement.
GOING
FORWARD
GOING
FORWARD
•
The Data Collection Manager shall be
contacted by the contractor and/or
sub-contractor prior to any installation.
This includes the cabinet, loops and
piezos.
GOING
FORWARD
•
•
The Data Collection Manager shall be
contacted when the site has been
installed and ready for inspection.
In most cases, there is a bonus tied to
the project. If the site does not
pass….your company may lose or be
the cause of any bonus not being paid.
GOING
FORWARD
•
In your travels throughout the district, if you
find a damaged site, please do the
following:
• Take a picture of the damage.
• Call Road Rangers or local police if the site was
involved in an accident.
• Contact the Data Collection Manager
immediately.
• In most cases, if the damage was caused by an
accident, we can recoup the cost of repair from
the at-fault insurance company.
CONTACT
INFORMATION
RUBIE FRASE – I am the main
contact person for District 5
•
386-943-5380 – Office
386-847-4289 - Cell
•
Rubie.frase@dot.state.fl.us
•
TECHNICAL
PRESENTATION
Presented by
Terry Robinson – Southern
Traffic Services
PRE-ENGINEERING
Planning
Materials
Action
PRE-ENGINEERING
PLANNING
•
•
•
Sites are selected by the Data Collection
and Planning Office in most scenarios.
Sites are approved by the District
Engineers.
Plans are developed by the Office of
Design and reviewed by the Data
Collection Office.
PRE-ENGINEERING
•
•
PTMS sites are independent of one
another, and sites are built to fit the
location.
Numerous departments are involved
with the building of a PTMS site.
Statistics office, Planning office, Data
office, Design office, Engineering
office, Construction division, etc.
PRE-ENGINEERING
•
•
•
Utility locates are completed
Pavement is cured and ready for
sensors
All equipment is on hand and meets
Approved Product List (APL) and
Qualified Product List (QPL)
PRE-ENGINEERING
•
•
•
Engineers have approved ALL Plans
and changes
Schedules have been approved by:
Project Manager, Project Engineer,
Traffic Operations Engineer,
Consultant
Maintenance of Traffic Plan submitted
and Approved.
WHAT ARE THE COMPONENTS
OF A PTMS SITE?
MATERIALS
•
•
•
•
•
•
•
Cabinet – Type III, IV, and V
Piezoelectric sensors
Inductive Loop sensors
Pull boxes
Grounding electrodes
Surge Protection
Conduit
MATERIALS
•
•
•
•
•
•
Is cabinet in place?
Does cabinet face the right direction?
Does cabinet meet plans and specifications?
Pull boxes in place and installed to
specifications?
All conduits in place?
Have piezo sensors been tested prior to
installation
MATERIALS
•
•
•
Do loop wires and cables meet
QPL?
Are epoxies and sealants
approved?
Are dates on piezos, sealants and
epoxies recorded?
ACTION
•
•
•
•
•
Areas of Concern
Maintenance of Traffic (MOT)
Review of MOT Plan
Placement of Temporary Traffic
Control Devices
Any ADDITIONAL SIGNS REQUIRED?
District or Area Public Information
Office Contacted?
ACTION
•
•
•
Verify all Public Safety and Local
Governments are aware of Lane
Closures
Update Traffic Operations if changes
are made to MOT Plan
Notify ALL parties that all lanes are
open upon completion
BREAK TIME
INDUCTIVE LOOP
ASSEMBLIES
•
•
•
Inductive loops are simply a coil of wire
embedded in the road’s surface.
The loops that are installed in the State of
Florida and used by the FDOT are usually 6’
X 6’ loops using 12 gauge wire consisting of
4 turns.
2 loops are installed in each lane that work
in conjunction with the Piezoelectric
Sensors.
INDUCTIVE LOOP
ASSEMBLIES
•
•
•
What is an inductor?
An inductor is simply a coil of wire or an
electromagnet.
The inductor or wire has a very low
resistance. When a vehicle passes over the
loop, the inductance is elevated. This unit
of increase is measured in “Henry’s”, or
microhenries. The vehicle becomes the
“inductor” or the coil.
LAYOUT OF SENSORS
•
•
•
Verify the space of the sensors
Standard spacing is 16 feet from
leading edge of leading loop to leading
edge of trailing loop
Loops MUST be in CENTER of lane and
MUST NOT cross expansion joints
unless approved by Engineer prior to
installations
LAYOUT OF SENSORS
•
•
•
•
Standard loops are 6 foot by 6 foot, 4
turns on each loop
Loops cut in asphalt SHALL be cut to a
depth of 3 inches or deeper
Loops cut in concrete SHALL be cut 2.5
inches or deeper
Piezo Sensors shall be placed on one side
of the lane and NOT placed in the middle
of the lane
LAYOUT OF SENSORS
LOOP
PIEZO
LOOPS & LOOP
INSTALLATIONS
•
•
•
•
Loops shall be installed as per FDOT
Standards and Specifications
FDOT District 5 Standards REQUIRE
that LOOPS ARE NOT TO BE SPLICED
Loop wires are to be checked prior to
installation
Loops are to be placed in the BOTTOM
of the slots
LOOPS & LOOP
INSTALLATIONS
•
•
•
•
Insure there are not any scars, rips,
insulation abrasions, or kinks in the wire
assembly
All loops will be DRILLED in the corner using
a 1.5 inch diameter bit
Make sure slots are clear of debris, rocks,
and asphalt deposits
Verify depths are uniform throughout the
entire cut
LOOPS & LOOP
INSTALLATIONS
•
•
•
No loops shall be installed in WET asphalt or
concrete
Do not apply sealants if roadway has
residue or moisture in slots or on surface
around cuts
A minimum of 2 inches of clearance from
the top of the loop wire in the slot to the
surface of the roadway is required
LOOPS & LOOP
INSTALLATIONS
•
•
•
Loops shall be twisted a minimum of 6
to 12 turns per foot throughout the
entire homerun length
Loops shall be marked in pull box and
inside the cabinet
Homeruns shall be placed in the
bottom of each cut
LOOPS & LOOP
INSTALLATIONS
•
•
The homerun cut will start at 3 inches
deep and for each additional homerun
added to the slot and additional ½
inch will be cut to the depth
This process will allow for fewer
homerun cuts to the roadway
PIEZO
LOOP
HOMERUN
CONDUIT
PULL BOX
LOOPS & LOOP
INSTALLATIONS
•
•
•
We test all loops upon final inspection
We are checking the insulation, signal
strength and circuit of the loops
We WILL NOT pass any loop that does
no meet Entire Minimum Specifications
PIEZO INSTALLATIONS
•
•
Piezoelectric sensors most commonly
used by FDOT are Measurement
Specialties Incorporated (MSI) – BL
Roadtrax
Sensors – BL is short for Brass Linguini
PIEZO INSTALLATIONS
PIEZO INSTALLATIONS
•
Piezoelectric systems use piezoelectric
sensors. The sensors are embedded
in a conducting material. When
weight is applied the pressure changes
the voltage of the electric charge
flowing through the conductor. The
sensors measure the change in
voltage and calculate the load.
PIEZO SENSORS
•
•
The base technology is piezoelectric
polymer. The Brass Linguini is a highly
compressed piezoelectric polymer in a
coaxial configuration, with brass outer
casing.
The BL is flat, about 1/16” (1.5mm) thick
and ¼ “ (7mm) wide. The sensors are put
into the road in a ¾” (19mm) wide and 1.5”
(25mm) deep slot cut in the road.
PIEZO SENSORS
Installations
•
•
•
Piezo sensors are to be installed to
Manufacture Specifications
All warranty cards and manufacture
paperwork shall be left in the cabinet upon
installation
All testing of sensors are to be performed in
front of a Representative of the FDOT
PIEZO SENSORS
•
Installations
Epoxies to be used are as follows:
• AS475: asphalt, modified mixes,
superpave roadways
• G100-EBOND: concrete
•
•
NO SPLICING OF PIEZO SENSORS
All piezo sensors MUST be marked in
each pull box and inside of cabinet
PIEZO SENSORS
•
•
Installations
Re-test all piezo sensors in cabinet
***Piezo sensors shall be pushed
down to .250 inches below surface of
roadway*** This is a NEW application
in FDOT Standards!!!
PULL BOX AND
CONCRETE APRONS
•
•
•
Pull boxes may be made of Quazite material
or concrete with a steel lid
All pull boxes must have locking bolts and
screws
Each pull box is required to have a concrete
apron that is 12 inches off each edge, 4
inches deep and slopes away to the surface
around the pull box
PULL BOX AND
CONCRETE APRONS
•
•
Pull boxes shall have a minimum of 8
inches of washed gravel inside of the
base
All pull boxes shall have clearly
marked cables and conduits
CABINETS
•
•
•
All cabinets should meet the
Specifications on the plans
All cabinets shall be mounted 48
inches off the ground measured to the
handle of the cabinet to ground
The cabinet shall have proper
grounding and grounding electrodes in
place
IN-ROAD SENSOR
TEMPLATES
•
•
•
The most common configuration used
is the Loop-Piezo-Loop.
Piezo-Loop-Piezo configurations are
also used in some scenarios.
WIM or Weigh in Motion sites most
commonly use Piezo-Loop-Piezo
configurations.
IN-ROAD SENSOR
TEMPLATES
•
•
PTMS sites that collect volume and
speed only by lane are made up of
loop-loop configurations.
The type of sensors to be installed will
be determined by the appropriate
parties and placed in the design plans.
SITE LAYOUT AND
MEASUREMENTS
•
•
•
•
Determine where the Piezo sensor will
be placed in the lane.
Piezos are always laid perpendicular to
the lane.
Mark the line with crayon or paint
using a straight edge.
Add 6 inches to the length of the piezo
to insure the length is correct.
SITE LAYOUT AND
MEASUREMENTS
•
•
•
•
The piezo MUST BE located between the
loops in the travel lane.
Measure upstream from the piezo 5 feet and
mark this spot with crayon or paint.
Measure from the piezo 11 feet and mark
with crayon or paint.
Using the center point we have already
determined, we will now layout the loop.
SITE LAYOUT AND
MEASUREMENTS
•
•
The loop is marked and painted.
Using a steel tape we will now measure 16
feet downstream and make a mark, this is
the leading edge for the trailing loop. We
will now measure 22 feet from the leading
loop (this is 6 feet behind the mark we just
made). We now have the second loop
ready to mark and paint.
SITE LAYOUT AND
MEASUREMENTS
•
•
•
We will use a straight edge that is at least 6
feet long to mark each leg of the loops.
A Laser may also be used to insure the
loops are parallel in the lane.
We now have a loop-piezo-loop
configuration.
SITE LAYOUT AND
MEASUREMENTS
•
•
Check the loops from the stripe using a
steel tape, each loop should be the same
distance from the edge line or skip line, if
not check the measurements and adjust
until the distances are the same.
See diagrams for reference.
CONSTRUCTION
CHECKLIST - PIEZOS
1.
2.
3.
4.
5.
Type I or II
Cable length of piezo sensors
Approved Epoxy on Approved
Products List
Depth of saw cut – 7/8” – 1.25” to
1.5”
Width of saw cut – ¾” – 7/8”
CONSTRUCTION
CHECKLIST - PIEZOS
Piezo tested prior to installations
7. Warranty cards filled out completely
8. Slots clean of debris and water
9. Epoxy mixed to manufacturer’s
standard
10. Duct tape applied to each side of
piezo cut
6.
CONSTRUCTION
CHECKLIST - PIEZOS
Epoxy poured in several lifts or layers
12. Sensor cables at correct depth
13. Sensors retested after epoxy is
applied
14. Manufacturer install sheets completed
15. Cables marked with lane of piezo
11.
CONSTRUCTION
CHECKLIST - LOOPS
1.
2.
3.
4.
Loops are corrected cut and corners
drilled.
Loops are cut at correct depth
Loop wire is 12 gauge wire that is
gasoline and oil resistant
Loop wire is placed into bottom of
slot, no visible kinks or knots in wire
CONSTRUCTION
CHECKLIST - LOOPS
5.
6.
7.
8.
9.
Wire is applied with a blunt object
(not a screwdriver, knife, etc.)
Loop wire is turned 4 times in grid
Loop wire is continuous with no
splices in roadway
Loop slots are clean and compressed
air used to blow out slots
Loop slots are dry
CONSTRUCTION
CHECKLIST - LOOPS
Loop wire is placed in slot only when
all saws and blowers are no longer in
use
11. Loop wires are twisted at homerun
junction – 6-12 twists per foot
12. Wire is re-inspected for cuts, nick,
knots.
10.
CONSTRUCTION
CHECKLIST - LOOPS
Wire is placed into conduit and gently
pulled to pull boxes.
14. Loop wires are marked in pull box
and coiled with 12-18 inches of
excess wire
15. Wire is tested for inductance and
continuity
13.
CONSTRUCTION
CHECKLIST – PULL BOXES
1.
2.
3.
4.
5.
6.
Pull box meets specification
Pull box is placed in solid ground
Pull box has correct depth of washed gravel
Pull box has a 5’ concrete pad surrounding it
Pull box is level and allows water to run off
and not collect in or on pull box
Grass and aggregates are placed around pull
box to prevent erosion
CONSTRUCTION
CHECKLIST - CABINETS
1.
2.
3.
4.
5.
Cabinet should meet Specifications
Cabinet should be securely anchored
Cabinet should be properly grounded
Cabinet should be mounted with the center
of the cabinet at 48” from the ground
Cabinet should be facing away from the
roadway
PTMS CHECKLIST
•
•
•
•
•
Are piezo lengths correct? ______
Are piezo cables long enough to reach the
cabinet? ______
Is the epoxy being used approved and
mixed properly? ______
Is loop wire 12 gauge and gasoline and oil
resistant? ______
Are loops located in the center of the lane?
______
PTMS CHECKLIST
•
•
•
•
•
Have piezos been checked prior to
placement in road? ______
Has warranty card and paperwork been
completed? ______
Is roadway clean and all equipment turned
off before sensors installed? ______
Are saw cuts clean and is depth the same
throughout entire loop/piezo? ______
Are corners of loops drilled with a 1 1/2”
bit? ______
PTMS CHECKLIST
•
•
•
•
•
Do loop wires lay in bottom of slots without
rise and falls? ______
Is loop wire twisted at homerun
intersection? ______
Do loop wires have any kinks or cuts? ____
Is loop sealant applied evenly and covers all
the slots? ______
Is the excess loop sealant removed from the
roadway? ______
PTMS CHECKLIST
•
•
•
•
•
•
•
•
Is epoxy mixed correctly? ______
Is epoxy on the APL list? ______
Was the piezo epoxy applied in layers? ___
Is epoxy cured and dry? ______
Is loop wire labeled? ______
Are pull boxes approved? ______
Are pull boxes correctly installed? ______
Washed gravel in pull boxes? ______
PTMS CHECKLIST
•
•
•
•
•
•
Did the contractor assign lane numbers
inside the cabinet to piezos/loops? ______
Is cabinet level? ______
Is cabinet accessible? ______
Is the dirt and grass replaced? ______
Is dirt compacted to avoid erosion
issues? ______
Are all dust, residue and compounds out of
the roadway? ______
PTMS CHECKLIST
•
•
•
•
Is cabinet and grounding according to
specifications? ______
Is conduit being used approved? ______
Are all schematic, paperwork, and warranty
cards placed in cabinet? ______
Does cabinet lock and secure properly? ___
QUESTIONS?